Generally, an air conditioner maintains an indoor temperature as a preset state thereby to maintain an indoor room as a comfortable state.
The air conditioner includes a refrigerating cycle system. The refrigerating cycle system is composed of: a compressor for compressing a refrigerant; a condenser for condensing the refrigerant compressed in the compressor and emitting heat to outside; an expansion valve for lowering a pressure of the refrigerant condensed by the condenser; and an evaporator for evaporating a refrigerant that has passed through the expansion valve and absorbing external heat.
The compressor, the condenser, the expansion valve, and the evaporator are connected to one another by a connection pipe thereby to form one cycle.
In the refrigerating cycle system, when the compressor is operated as power is supplied to the compressor, a refrigerant of a high temperature and high pressure discharged from the compressor sequentially passes through the condenser, the expansion valve, and the evaporator, and then is sucked into the compressor. The above processes are repeated. During the above process, heat is generated in the condenser, and cool air is formed as the evaporator absorbs external heat. The heat generated in the condenser and the cool air formed in the evaporator are selectively circulated into an indoor room, thereby maintaining the indoor room as a comfortable state.
The air conditioner can be implemented as various shapes according to an installation condition. For example, the air conditioner is mounted in one casing with the refrigerating cycle system, and an air duct and a blowing fan are provided in the casing. The air conditioner is generally installed at a window of an indoor side in order to maintain a relatively small indoor room as a comfortable state.
As another example, the air conditioner is composed of an indoor unit and an outdoor unit. The indoor unit includes a heat exchanger serving as an evaporator at the time of performing an air conditioning. The outdoor unit includes a heat exchanger serving as a condenser at the time of performing an air conditioning, and a compressor. The indoor unit is installed at an indoor room, and the outdoor unit is installed at an outdoor room.
As still another example, the air conditioner is composed of: one outdoor unit; and a plurality of indoor units connected to the outdoor unit and respectively installed at an indoor room. A compressor mounted at the outdoor unit has a great capacity, or two compressors are mounted at the outdoor unit.
Generally, a compressor converts an electric energy into a kinetic energy, and compresses a refrigerant by the kinetic energy. The compressor includes a motor part for generating a driving force; and a compression part for compressing a refrigerant by receiving the driving force of the motor part. The compressor can be divided into a rotary compressor, a scroll compressor, a reciprocal compressor, etc. according to a compression mechanism of a refrigerant.
Among the above compressors, the rotary compressor, the scroll compressor, etc. are mainly used in the air conditioner.
In the fabrication process of the air conditioner, the most important factor is to minimize a fabrication cost for a high competitiveness, and is to minimize an energy consumption at the time of operating the air conditioner.
Especially, as the oil usage amount is increased worldwide and thus the oil price is increased, an air conditioner capable of minimizing an energy consumption is being much required. When the energy consumption of the air conditioner is minimized, the environment pollution is minimized.
In order to minimize the energy consumption of the air conditioner, the air conditioner has to be driven according to a load of an indoor room where the air conditioner is installed, that is, according to a temperature of an indoor room. That is, when a temperature of an indoor room is drastically increased, the air conditioner is driven to generate much cold air in order to maintain a preset indoor temperature. On the contrary, when a temperature of an indoor room is minutely varied, the air conditioner is driven to generate less cold air in order to maintain a preset indoor temperature.
To satisfy the above condition, an amount of a refrigerant discharged from a compressor, a main component for driving a refrigerating cycle system is controlled.
In order to control a discharge amount of a refrigerant from the compressor, an inverter motor for varying an rpm of a driving motor constituting the compressor is used. The rpm of the driving motor of the compressor is controlled according to a condition of an indoor room where the air conditioner is installed, thereby controlling an amount of a refrigerant discharged from the compressor. As the discharge amount of the refrigerant is varied, heat generated in the condenser and cold air generated in the evaporator are controlled.
However, in case of applying the inverter motor to the driving motor of the compressor, the fabrication cost of the air conditioner is increased since the inverter motor is very expensive thereby to lower the price competitiveness.
According to this, it is required to vary a capacity of an air conditioner according to a condition of an indoor room where the air conditioner is installed by controlling an amount of a refrigerant discharged from a compressor under a state that a general motor that is not provided with a control drive is applied to the compressor.